Question: Let $f(x) = -4x^{2}+10x+6$. Where does this function intersect the x-axis (i.e. what are the roots or zeroes of $f(x)$ )?
Explanation: The function intersects the x-axis when $f(x) = 0$ , so you need to solve the equation: $-4x^{2}+10x+6 = 0$ Use the quadratic formula to solve $ax^2 + bx + c = 0$ $x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$ $a = -4, b = 10, c = 6$ $ x = \dfrac{-10 \pm \sqrt{10^{2} - 4 \cdot -4 \cdot 6}}{2 \cdot -4}$ $ x = \dfrac{-10 \pm \sqrt{196}}{-8}$ $ x = \dfrac{-10 \pm 14}{-8}$ $x =-\frac{1}{2},3$